1. Technical Field
The invention relates to an image capturing apparatus and a capturing method. Particularly, the invention relates to an image capturing apparatus and a capturing method for capturing an eye image.
2. Related Art
The eye is a window to a soul, and through the eyes, people can feel light and color of the world. Cone cells and rod cells in the eye used for perceiving lights and color are all located on retina of a fundus, which are unique tissues capable of converting light into physiological electric signals. Blood vessels used for supplying blood and nutrients to the eye are also located on the fundus. When the fundus has a problem of vessel proliferation or rupture, for example, has symptoms of macular degeneration and haemorrhage, etc., it is likely to cause death of the cone cells and rod cells on the retina, which may result in loss of vision of a patient. Therefore, in eye disease diagnosis and preventive health care, observation and tracking of images of the fundus are very important.
Generally, limited by a pupil size, in a single one-angle shooting of a conventional fundus image shooting method, even if pupil dilation drug such as a mydriatic agent is used, a fundus image range that can be captured is only a viewing angle of about 30 to 40 degrees. Therefore, if an image of an edge of the fundus is to be captured, the patient is asked to stare a reference point, and then the point where the eye stares is continually moved around in a slow and stable speed, so as to continually obtain a plurality of images of the fundus. Then, a data processing device such as a computer, etc. is used to synthesize the images of the fundus through specific image synthesis software. However, an illumination light used for repeatedly capturing the images of the fundus may also cause discomfort and fatigue of the eye of the patient, which may cause unconscious blink of the eye or nystagmus to influence an image capturing quality. Moreover, since the images of the fundus are obtained through multiple shoots, an exposure value and a white balance for each shooting are different, and the obtained images need to be corrected before being synthesized by a large-scale calculator such as a computer, etc., such that difficulty in correction is increased to influence the quality of the synthesized image. If the quality of the synthesized image is influenced, a medical staff is not easy to identify a microvascular image of the fundus, which may cause judgement difficulty and even delay a timing of treatment of the patient. Therefore, it is important to quickly obtain a complete and clear image of the fundus.